1. Technical Field
The present invention relates to sanding units for cabinet doors and, more particularly, to a combination drum and orbital sander unit for cabinet doors which includes a first drum sanding unit for coarsely sanding the cabinet door, a second set of orbital sanding units which engage the cabinet door and provide finish sanding and a belt unit for moving the cabinet door being sanded under the sanding unit.
2. Description of the Prior Art
In the prior art, as shown in FIG. 5, when a drum sander sands a wood door surface, the portions of the door having the grain aligned with the rotation of the drums (specifically the xe2x80x9cstylesxe2x80x9d) are coarsely sanded resulting in some scratching but the scratching is aligned with the grain and can easily be sanded out. However, the scratching formed on the xe2x80x9crailsxe2x80x9d is cross-grain and is very difficult to sand out, necessitating a large investment of time and energy by the individual doing the finish sanding. An example of such cross-grain scratching is shown in FIG. 6. At present, there is no example found in the prior art of a drum sander which will not create this cross-grain scratching.
The maker of the door is thus forced to manually sand the rails of the door to remove the cross-grain scratching, which takes considerable time and effort. Moreover, the speed with which doors can be manufactured is greatly reduced, and in smaller shops, this increases the cost of manufacture and decreases profit margins. There is therefore a need for a finishing sander device which will remove the cross-grain scratching from the door during the manufacturing process without requiring a large investment of manual labor.
Also, there is a need for a finishing sanding device which utilizes orbital sanders as opposed to the traditional drum-type sander, as these sanders are generally more suited to finishing work. Of course, use of orbital sanders will only be acceptable if the entire surface of the door can be finished during the manufacturing process, and this can be done best with a plurality of overlapping orbital sanders which finish the door in one pass. At present, there is no example found in the prior art which incorporates such an arrangement of sanders.
Therefore, an object of the present invention is to provide an improved orbital finishing sander.
Another object of the present invention is to provide an orbital finishing sander which includes a frame on which is mounted a conveyor belt, the conveyor belt operative to move a door to be sanded under the sanding devices which are mounted thereabove.
Another object of the present invention is to provide an orbital finishing sander having a plurality of vertically movable orbital sanders mounted on a plate above the conveyor belt, the sanders being moved downwards into sanding position upon detecting a door passing thereunder.
Another object of the present invention is to provide an orbital finishing sander which will quickly and easily remove cross-grain scratches of the kind formed by drum sanding units.
Another object of the present invention is to provide an orbital finishing sander which incorporates the plurality of orbital sanders mounted in overlapping relation to sand all of the door surface during the sanding process.
Another object of the present invention is to provide an orbital finishing sander which is a stand-alone unit and does not have to be used in connection with a drum sander.
Finally, an object of the present invention is to provide a orbital finishing sander which is relatively simple to manufacture and which is safe and durable in use.
The present invention provides an orbital finishing sander for finishing coarsely sanded wood pieces which includes a support frame and a conveyor belt movably mounted on the frame and extending generally horizontally thereon. An orbital sander support such as a plate is mounted on the frame and extends over and above the conveyor belt for supporting at least one orbital sander vertically movably mounted on the orbital sander support, the orbital sander being movable between a lowered engagement position and a raised non-engagement position. At least one orbital sander movement device such as a pneumatic ram would be operatively connected to each one orbital sander for moving the associated orbital sander between the lowered engagement position and the raised non-engagement position. The present invention also includes at least one switch device operatively connected to the orbital sander movement devices to engage the orbital sander movement devices to move the orbital sanders between the lowered engagement position and the raised non-engagement position in response to the switch devices detecting a wood product to be sanded. Finally, the switch devices and the orbital sander movement devices cooperate to move the orbital sanders downward into the lowered engagement position with a coarsely sanded wood product when the switch devices detect the wood product being positioned beneath the orbital sanders and moving the orbital sanders upward into the raised non-engagement position when the switch devices detect the wood product not being positioned beneath the orbital sanders.
The orbital finishing sander as thus described clearly offers several advantages over those devices found in the prior art. The relatively simple design of the orbital finishing sander permits the use of the invention by woodworkers of all varieties, from large companies to individual users. Also, because the present invention is designed to be used as a finishing device mounted on the sanding unit which utilizes a drum sander or the like for coarse sanding, the processing of the wood products through the sanding devices is not impeded and the speed of production is markedly increased. Furthermore, as the present invention is generally automated, it frees up the manufacturer to perform other tasks during the sanding process, which is invaluable for smaller. businesses. The present invention thus provides a substantial improvement over those devices found in the prior art.